The present invention relates to photonics chips and, more specifically, to structures for a waveguide crossing and methods of fabricating a structure for a waveguide crossing.
Photonics chips are used in many applications and systems including, but not limited to, data communication systems and data computation systems. A photonics chip integrates optical components, such as waveguides, optical switches, directional couplers, and bends, and electronic components, such as field-effect transistors, into a unified platform. Among other factors, layout area, cost, and operational overhead may be reduced by the integration of both types of components on the same chip.
A waveguide crossing is building block used in photonics chips to provide paths for propagating optical signals. A waveguide crossing is an optical element in which two waveguide cores in a single layer intersect and directly cross. An ideal waveguide crossing may be designed with measures (e.g., shaping) to provide high transmission in each straight path and low crosstalk to the corresponding crossing path. However, despite these measures, directly-crossing waveguide cores may unwantedly exhibit scattering, crosstalk, and multi-mode excitation. In addition, directly-crossing waveguide crossings possess large footprints that may hamper dense integration in a photonics chip.
Improved structures for a waveguide crossing and methods of fabricating a structure for a waveguide crossing are needed.